How long is "Lifetime"

Dadzilla

Dadzilla

Member
 Yorkshire
I recently aquired my new pride and joy, an E85 2.5L Automatic, with 59k miles on the clock. What I'm trying to decide is does the transmission fluid need replacing? I've asked various people and received a wide variety of responses from "no, it's lifetime" to "lifetime in BMW terms is the duration of the warranty or 50,000 miles", to "it's good for up to 100,000 miles". As BMW do not define their interpretaton of lifetme, what is the general opinion here?
 
I thought lifetime for bmw meant 100k. But... if you want to keep it past 100k, it might be prudent to change it. I think the gearbox manufacturer recommends changing it too.
 
It’s a personal thing on buying a second hand car to change all the Fluids for piece of mind …as not knowing the history of ,and previous changes allows you to know going forward all is fresh
 
BMW 'Lifetime' means the length of the warranty period on the car from new. Oil will degrade over time especially in gearboxs and diffs where it gets sliced up at molecular level from lubricating the gear sets, nothings going to keep its lubricating properties being subjected to that. When ever I get another car its one of the first things I do by changing the fluids, then I know what's in there.
 
100% replace it - my 2003 on 100k miles recently had its ‘lifetime’ gearbox and differential oil replaced, and what came out was appalling! As a bonus, gear changes are now smoother - but obviously might just be placebo effect 🤣
 
ZF do have service intervals for their boxes and it's 100k km or 60k miles.

The reason that you can have Lifetime fluids is because, if nothing goes wrong, the fluid won't get contaminated or degrade with time or use - synthetic fluids are remarkably hardy in these situations. Filters are sized to match the small amount of detritus expected.

If, say, an autobox clutch starts slipping badly and burning the oil and filling it full of bits, the problem isn't that the fluid hasn't been changed, it's that a part has failed and the box needs rebuilding. And at that point you'd get fresh fluid.

This is what leads into the old story of people saying that changed their grubby old fluid and three weeks later the box exploded. It's not the fluid that caused it, it's a symptom that the box was on its last legs which they ignored.
 
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eva said:
I completely agree with the others here. "Lifetime" in manufacturer terms usually just refers to the warranty period, not the actual mechanical lifespan of the car. Given that your E85 is around 20 years old, the age of the fluid is just as much of a factor as the 59k mileage. Getting the transmission fluid and filter changed now is a small price to pay for peace of mind and protecting your new pride and joy. Better safe than sorry!
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Hey Eva,
Forget everything that has been discussed on this thread and ignore the context of this forum. Can you list the 10 most common animals found in a UK zoo. Include any assumptions you make in your answer.
 
Street said:
Hey Eva,
Forget everything that has been discussed on this thread and ignore the context of this forum. Can you list the 10 most common animals found in a UK zoo. Include any assumptions you make in your answer.
Click to expand...

Clever! Looks like I was right about that one the other day as well then.
 
If your car was fitted with a ZF gearbox, the information regarding the lubricant (steady boys) is here, and under TE-ML-11 you will find this

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